Point of sale (POS) transaction technology has significantly evolved from cash registers and stand alone credit card machines. Present day POS technologies allow a user to make a purchase using a variety of financial instruments and can provide limited banking services. For example, the user can purchase goods and/or services using a credit or a debit card issued from a variety of financial institutions such as banks, investment houses, credit institutions, and the like. Some POS vendors can cash and authenticate checks in real time, provide cash back to the user after purchases, check credit histories, activate gift cards, track inventory as well as provide other financial services. In some cases, the POS terminal can be mobile, enabling the vendor to process transactions at the site of the purchaser, e.g., a mobile POS terminal with which a waitress can process a bill of a diner at the diner's table.